View source for Spacewatch

{{Short description|Astronomical survey that specializes in the study of minor planets}}
{{Infobox astronomical survey
 |image = Spacewatch 1.8m telescope.jpg
 |caption = Spacewatch 1.8-meter telescope
}}
{| class="wikitable floatright" style="font-size: 0.9em; width: 320px;"
|+ [[Minor planet]]s discovered: 169,873<ref name="MPC-Discoverers" />
|-
| ''see [[:Category:Discoveries by the Spacewatch project]]''
|}

The '''Spacewatch''' Project is an [[astronomical survey]] that specializes in the study of [[minor planet]]s, including various types of [[asteroid]]s and [[comet]]s at [[University of Arizona]] telescopes on [[Kitt Peak]] near [[Tucson, Arizona]]. The Spacewatch Project has been active longer than any other similar currently active programs.<ref>{{Cite web |last=McMillan |first=Robert |date=2001 |title=The Spacewatch Project |url=https://space.nss.org/wp-content/uploads/Space-Manufacturing-conference-13-239-The-Spacewatch-Project.pdf |access-date=6 June 2022 |website=National Space Society}}</ref>

Spacewatch was founded in 1980 by [[Tom Gehrels]] and [[Robert S. McMillan (astronomer)|Robert S. McMillan]], and is currently led by astronomer Melissa Brucker at the [[University of Arizona]]. Spacewatch uses three telescopes of apertures 0.9-m, 1.8-m, and 2.3-m. These telescopes are located on [[Kitt Peak]], with the first two dedicated to the purpose of locating [[Near-Earth object|Near-Earth Objects (NEOs)]].<ref>{{cite web |url=http://spacewatch.lpl.arizona.edu/ |title=The Spacewatch Project |publisher=University of Arizona |year=2010}}</ref><ref name="McMillan et al 2015">{{cite journal |last1=McMillan |first1=Robert S. |last2=Larsen |first2=Jeffrey A. |last3=Bressi |first3=Terrence H. |last4=Scotti |first4=James V. |last5=Mastaler |first5=Ronald A. |last6=Tubbiolo |first6=Andrew F. |title=Spacewatch Astrometry and Photometry of Near-Earth Objects |journal=Proceedings of the International Astronomical Union |date=August 2015 |volume=10 |issue=S318 |pages=317–318 |doi=10.1017/S1743921315006766 |s2cid=125071840 |doi-access=free }}</ref>

The 36 inch (0.9 meter) telescope on [[Kitt Peak]] has been in use by Spacewatch since 1984, and since 2000 the 72&nbsp;inch (1.8 meter) Spacewatch telescope.<ref name=ScienceDaily2018>{{cite news |url=https://www.sciencedaily.com/releases/2000/10/001010072508.htm |title=Spacewatch telescope detects its first asteroids |website=ScienceDaily |access-date=2018-11-18 |language=en |df=dmy-all}}</ref> 
Spacewatch's 1.8-meter telescope is the largest in the world that is used exclusively for asteroids and comets.<ref name="McMillan">{{cite conference
|conference=Symposium S236: Near Earth Objects, our Celestial Neighbors: Opportunity and Risk, August 2006
|isbn=978-0-521-86345-2
|issn=1743-9213
|title=Spacewatch preparations for the era of deep all-sky surveys
|book-title=Proceedings of the International Astronomical Union
|volume=2
|number=S236
|publisher=Cambridge University Press
|last=McMillan
|first=Robert S.
|year=2007
|page=329
|url=https://books.google.com/books?id=QQx8r1_TPQEC&pg=PA329
|doi=10.1017/S1743921307003407
|doi-access=free}}</ref> It can find asteroids and comets anywhere from the space near Earth to regions beyond the orbit of Neptune and to do astrometry on the fainter of objects that are already known. The telescope uses a CCD camera at folded prime focus.<ref name=telescopes>{{cite web |title=Home SPACEWATCH® |url=https://spacewatch.lpl.arizona.edu/telescopes |website=spacewatch.lpl.arizona.edu/telescopes |publisher=The University of Arizona |access-date=17 March 2025}}</ref>

The 0.9-meter telescope complements these deep observations using an array of four CCDs to cover a much larger field of view, 2.9 square degrees compared to the ~ 0.1 square degrees of the 1.8-meter.<ref name=telescopes></ref>

Each year, Spacewatch observes approximately 35 radar targets, 50 [[near-Earth objects]], and 100 potential spacecraft rendezvous destinations. From 2013 to 2016, Spacewatch observed half of all NEOs and [[potentially hazardous asteroid]]s (PHAs) observed by anyone in that time.<ref name="McMillan et al 2015" /> {{As of|2022}}, Spacewatch had discovered over 179,000 [[minor planets]] numbered by the [[Minor Planet Center]].<ref>{{cite web | url=https://minorplanetcenter.net/data | title=IAU Minor Planet Center }}</ref>

== History ==
The 1.8 meter Spacewatch telescope and its building on [[Kitt Peak]] were dedicated on June 7, 1997 for the purpose of finding previously unknown asteroids and comets.<ref>{{cite journal |last1=Perry |first1=Marcus L. |last2=Bressi |first2=Terrence |last3=McMillan |first3=Robert S. |last4=Tubbiolo |first4=Andrew |last5=Barr |first5=Lawrence D. |editor-first1=Hilton |editor-last1=Lewis |title=1.8-m Spacewatch telescope motion control system |journal=Telescope Control Systems III |date=26 May 1998 |volume=3351 |pages=450–465 |doi=10.1117/12.308809 |bibcode=1998SPIE.3351..450P |s2cid=62230373 }}</ref> Since January 1 2003, Spacewatch has made ~2400 separate-night detections of Near-Earth Objects.<ref name="McMillan" />

There was an upgrade to the 0.9 meter which was funded by [[NASA]] and the Kirsch Foundation.

The Spacewatch Project is the longest-running of all present programs of astrometry of solar system objects, and was the first to use [[Charge-coupled device|CCD]]s to survey the sky for comets and asteroids.<ref name="McMillan et al 2015" />

== Spacewatch in action ==
Spacewatch conducted a survey that was proposed May 12, 2006, and accepted on November 13, 2006. This survey used data taken over 34 months by the [[University of Arizona]]’s Spacewatch Project based at [[Steward Observatory]], Kitt Peak. Spacewatch revisited the same sky area every three to seven nights in order to track cohorts of main-belt asteroids. This survey discovered one new large [[Kuiper Belt]] Object (KBO) and detected six others. This proved that new sweeps of the sky are productive even if they have been previously examined simply due to the complexities of running large surveys over many nights and variable conditions.<ref>{{cite journal |last1=Larsen |first1=Jeffrey A. |last2=Roe |first2=Eric S. |last3=Albert |first3=C. Elise |last4=Descour |first4=Anne S. |last5=McMillan |first5=Robert S. |last6=Gleason |first6=Arianna E. |author6-link=Arianna Gleason|last7=Jedicke |first7=Robert |last8=Block |first8=Miwa |last9=Bressi |first9=Terrence H. |last10=Cochran |first10=Kim C. |last11=Gehrels |first11=Tom |last12=Montani |first12=Joseph L. |last13=Perry |first13=Marcus L. |last14=Read |first14=Michael T. |last15=Scotti |first15=James V. |last16=Tubbiolo |first16=Andrew F. |title=The Search for Distant Objects in the Solar System Using Spacewatch |journal=The Astronomical Journal |date=1 April 2007 |volume=133 |issue=4 |pages=1247–1270 |doi=10.1086/511155 |bibcode=2007AJ....133.1247L |s2cid=29114253 }}</ref>

== Notable discoveries ==
[[File:NEA by survey.png|thumb|310px|Number of [[near-Earth object|NEOs]] detected by various projects:
{| style="width: 100%; margin-bottom: 8px;"
|-
| valign=top width=40% |
{{legend2|#0000FF|border=1px solid #0000B3|[[LINEAR]]}}<br />
{{legend2|#FFA500|border=1px solid #B37400|[[Near Earth Asteroid Tracking|NEAT]]}}<br />
{{legend2|#FF0000|border=1px solid #800000|'''Spacewatch'''}}<br />
{{legend2|#FFFF00|border=1px solid #B3B300|[[LONEOS]]}}
| valign=top |
{{legend2|#008B00|border=1px solid #003D00|[[Catalina Sky Survey|CSS]]}}<br />
{{legend2|#FF00FF|border=1px solid #390052|[[Pan-STARRS]]}}<br />
{{legend2|#00CCCC|border=1px solid #333|[[NEOWISE]]}}<br />
{{legend2|#993300|border=1px solid #333|[[List of near-Earth object observation projects|All others]]}}
|}]]
* [[Callirrhoe (moon)|Callirrhoe]]<ref>{{cite web |last1=Cowing |first1=Keith |title=17th moon of Jupiter discovered |url=http://www.spaceref.com/news/viewnews.html?id=189 |website=Spaceref |access-date=3 November 2021 |archive-date=18 October 2019 |archive-url=https://web.archive.org/web/20191018003020/http://www.spaceref.com/news/viewnews.html?id=189 |url-status=dead }}</ref>
* [[5145 Pholus]]<ref>{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Pholus |series=JPL Small-Body Database Browser |title=5145 Pholus (1992 AD) |publisher=[[Jet Propulsion Laboratory]]}}</ref>
* [[9965 GNU]]<ref>{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=9965;orb=0;cov=0;log=0#elem |series=JPL Small-Body Database Browser |title=9965 GNU |publisher=[[Jet Propulsion Laboratory]]}}</ref><ref>{{cite web |url=http://people.roma2.infn.it/~masi/sdss_smass/ |title=SDSS/SMASS asteroid taxonomy |website=people.roma2.infn.it}}</ref>
* [[9885 Linux]]<ref>{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=9885%20Linux#content |series=JPL Small-Body Database Browser |title=9885 Linux |publisher=[[Jet Propulsion Laboratory]]}}</ref>
* [[9882 Stallman]]<ref>{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=9882%20Stallman#discovery |series=JPL Small-Body Database Browser |title=9882 Stallman |publisher=[[Jet Propulsion Laboratory]]}}</ref>
* [[9793 Torvalds]]<ref>{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=9793%20Torvalds#discovery |series=JPL Small-Body Database Browser |title=9793 Torvalds |publisher=[[Jet Propulsion Laboratory]]}}</ref>
* [[20000 Varuna]]<ref>{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=20000 |series=JPL Small-Body Database Browser |title=20000 Varuna |publisher=[[Jet Propulsion Laboratory]]}}</ref>
* [[60558 Echeclus]]<ref>{{cite web |url=http://www.ast.cam.ac.uk/~jds/coms06.htm |title=coms06 |website=www.ast.cam.ac.uk}}</ref>
* {{mpl|1998 KY|26}},<ref>{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1998%20KY26 |work=JPL Small-Body Database Browser |title=1998 KY26 |publisher=[[Jet Propulsion Laboratory]]}}</ref> target of [[JAXA]]'s [[Hayabusa2]] extended mission.
* [[65803 Didymos]],<ref>{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=65803 |series=JPL Small-Body Database Browser |title=65803 Didymos |publisher=[[Jet Propulsion Laboratory]]}}</ref> target of the [[Double Asteroid Redirection Test|DART]] mission
* {{mpl|(35396) 1997 XF|11}}<ref>{{cite web |url=http://www.minorplanetcenter.net/iau/mpec/J97/J97Y11.html |title=MPEC 1997-Y11: 1997 XF11 |publisher=[[Minor Planet Center]]}}</ref>
* {{mpl|(48639) 1995 TL|8}}<ref>{{cite web |url=http://www.minorplanetcenter.net/iau/mpec/J99/J99L24.html |title=MPEC 1999-L24: 1995 SM55, 1995 TL8, 1996 GQ21 |publisher=[[Minor Planet Center]]}}</ref>
* [[(136617) 1994 CC]]<ref>{{cite web |url=http://www.johnstonsarchive.net/astro/astmoons/am-136617.html |title=(136617) 1994 CC, "Beta", and "Gamma" |website=johnstonsarchive.net}}</ref>
* [[C/1992 J1]]<ref>{{cite web |url=http://spacewatch.lpl.arizona.edu/outerss_text.html |title=Spacewatch Outer Solar System Discoveries |department=Lunar and Planetary Laboratory |publisher=University of Arizona |url-status=dead |archive-url=https://web.archive.org/web/20081029054125/http://spacewatch.lpl.arizona.edu/outerss_text.html |archive-date=2008-10-29 |df=dmy-all}}</ref>
* [[C/2011 KP36|{{mp|C/2011 KP|36}}]]{{r|CBET_3109}}
* [[125P/Spacewatch]]<ref>{{cite web |url=http://cometography.com/pcomets/125p.html |title=125P/Spacewatch |website=cometography.com}}</ref>
* [[174567 Varda]]<ref>{{cite web |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=174567 |title=174567 Varda |series=JPL Small-Body Database Browser |publisher=[[Jet Propulsion Laboratory]]}}</ref>
* {{mpl|2013 BS|45}}<ref>{{cite web |url=http://www.minorplanetcenter.net/db_search/show_object?object_id=2013%20BS45 |title=2013 BS45 |publisher=IAU [[Minor Planet Center]]}}</ref>
* The project rediscovered [[719 Albert]], a long-[[lost asteroid]].<ref>{{cite web |title=Spacewatch Recovery of Long-Lost Asteroid (719) Albert |url=https://spacewatch.lpl.arizona.edu/news/spacewatch-recovery-long-lost-asteroid-719-albert |website=spacewatch |publisher=The University of Arizona |access-date=3 November 2021}}</ref>

== See also ==
* [[Planetary Data System]] (PDS)
* [[Spaceguard]]
* [[List of near-Earth object observation projects]]

== References ==
{{Reflist|refs=

<ref name="CBET_3109">{{cite journal
| author1= T. H. Bressi
| author2= R. Holmes
| author3= T. Vorobjov
| author4= L. Buzzi
| author5= S. Foglia
| author6= P. Miller
| author7= P. Roche
| author8= A. Tripp
| author9= R. Miles
| author10= G. V. Williams
| display-authors= 5
| editor1= D. W. Green
| title= Comet {{mp|C/2011 KP|36}} (Spacewatch)
| url= http://www.cbat.eps.harvard.edu/iau/cbet/003100/CBET003109.txt
| journal= Central Bureau for Astronomical Telegrams
| volume= 3109
| issue= 1
| date= 17 May 2012
| bibcode= 2012CBET.3109....1B }}
</ref>

<ref name="MPC-Discoverers">{{cite web |title=Minor Planet Discoverers (by number) |publisher=[[Minor Planet Center]] |url=http://www.minorplanetcenter.net/iau/lists/MPDiscsNum.html |date=12 January 2017 |access-date=3 February 2017}}</ref>
}} <!-- end of reflist -->

{{Planetary defense}}

[[Category:Planetary science]]
[[Category:Astronomical discoveries by institution]]
[[Category:Discoveries by the Spacewatch project|*]]
[[Category:Near-Earth object tracking]]